Its coordinates are 49&deg8'53" N and 2&deg2'18" W in DMS (Degrees Minutes Seconds) or 49.1481 and -2.03833 (in decimal degrees). Its UTM position is WV74 and its Joint Operation Graphics reference is NM30-08.

Current local time is 02:41; the sun rises at 07:51 and sets at 19:58 local time (Europe/Jersey UTC/GMT+0). The standard time zone for Gros Etacs is UTC/GMT+0
In 2017 DST starts on 26 Mar 2017 and ends on 29 Oct 2017.